Method and system for monitoring steam systems

ABSTRACT

A method and system for monitoring a steam system through remotely monitoring numerous points of a saturated steam system, wherein the method compares a steam temperature sensed at a portion of the steam system by a first sensor to a threshold subcooled temperature derived by a pressure sensed by a second sensor at or near the same portion of the steam system, wherein the method emits a warning to the first sensor when the sensed saturated temperature exceeds the derived threshold subcooled temperature.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority of U.S. provisional application No. 63/158,558, U.S. provisional application number filed 9 Mar. 2021, the contents of which are herein incorporated by reference.

BACKGROUND OF THE INVENTION

The present invention relates to steam systems that are designed to be operated as saturated systems (as opposed to steam systems that are designed to be superheated) and, more particularly, a method and system for monitoring a saturated steam system through remotely monitoring numerous points of a saturated steam system, wherein the method compares a measured steam temperature sensed at a portion of the steam system by a first sensor to a threshold subcooled (below saturated) temperature derived by a pressure sensed by a second sensor elsewhere in the steam system, wherein the method emits a warning to the first sensor when the sensed steam temperature is outside of the derived threshold subcooled saturated temperature.

Saturated steam is dry and most problems within a steam system can be avoided if the water (condensate) is kept out of it. The steam system must be monitored to ensure this is accomplished. Saturated steam systems should be operated at or close to a certain theoretical saturated temperature at a given saturated steam pressure. For example, saturated steam at 150 pounds per square inch gauge (psig, indicating that the pressure is relative to atmospheric pressure) has a saturated temperature of approximately 366 degrees F., 100 psig is 338F, 15 psig is 250 F, etc. This information is based upon saturated steam tables. Any temperature less than saturated temperature is “subcooled.” If a saturated steam system temperature is “subcooled”, this is an indication of excessive condensate and/or excessive air or other non-condensable gases. Air/gases and condensate are insulators and negatively affect heat transfer—affecting production efficiency and/or facility heating. Condensate entrained in steam can be very erosive thereby negatively affecting reliability. Excessive condensate can be extremely dangerous by putting personnel at risk of a water hammer event. Water hammer can result in damaged components, failed pipe supports, ruptured piping, site shutdowns, personnel injury and death, etc. Subcooled temperature can indicate specific system operational and/or design problems such as plugged or reduced-capacity steam traps, plugged or reduced-capacity Y-strainers, low quality (“wet”) steam, an unwanted reduction in the desired system pressure, undersized drip legs, too few drip legs, unwanted low points in the system, etc.

While other systems offer remote monitoring of steam trap operation or steam quality, they do not compare actual temperature readings determined by a first sensor of the steam system to calculated theoretical saturated temperatures (using saturated steam tables) based on the measured system pressure(s) based on a second sensor coupled to the steam system to identify a general subcooled condition throughout the non-modulating and/or modulating portions of the steam system.

Existing systems are designed primarily to monitor steam traps or steam quality. While some do use temperature and pressure, they do not use the comparison of actual temperature readings to calculate theoretical, threshold saturated temperatures based on steam system pressure(s). Existing systems do not focus on this comparison and cannot offer an alarm when saturated temperatures are outside of a defined threshold.

As can be seen, there is a need for a method and system for monitoring a saturated steam system through remotely monitoring numerous points of a saturated steam system, wherein each point senses a steam temperature and/or systemic pressure, wherein the method calculates a critical threshold subcooled temperature based on the systemic pressure and lookup tables, and wherein the method selectively indicates an alarm to each point having a sensed steam temperature lower than the threshold subcooled temperature.

Again, in a saturated steam system, the desire is for the system to be saturated, not “subcooled.” This system provides remote monitoring of numerous temperature points throughout the saturated steam system. Temperature sensors are used to report raw temperature readings. Pressure sensors are used to report raw pressure values. These raw pressure values will be used to determine a theoretically calculated saturated temperature based on the steam tables. In other words, the pressure readings will be used to determine what the temperature should be for the sensed saturated conditions. The temperature that is sensed throughout the system will be compared to the theoretically calculated temperature.

From this comparison, a steam system operator will have the ability to set an alert (alarm) for when this difference is outside of a determined threshold. This alarm will draw attention to a particular temperature sensor (area of the system), alerting personnel to address the issue with the goal of determining the root cause of the “subcooled” condition. This is critical because an individual monitoring a portion of the steam system cannot “see” the systemic pressure or in situ temperature without a gauge. It is also important to understand that individuals tending to the different portions of these steam systems are typically not engineers and may lack the training and mathematical or scientific acumen to reliably calculate the unacceptable subcooled temperature in a timely manner.

The present invention remotely monitors steam system pressure and temperature readings and uses software to compare these temperature readings to calculated theoretical saturated temperatures (using saturated steam tables) based on the measured system pressure(s). The system embodied in the present invention contemplates systemic pressure changes and thus recalculated saturated temperature changes. Other systems do not use this comparison. This design is simple and inexpensive. Temperature sensors are non-intrusive—they are installed on the surface of the piping.

The present invention does not only focus on steam trap operation or steam quality. Its purpose is to remotely monitor subcooled conditions, that can negatively affect heat transfer and safety of the saturated steam system, wherein the system is enabled to alert operators to multiple possible problems. In other words, the present invention enables validation of proper system operation.

SUMMARY OF THE INVENTION

In one aspect of the present invention, a subcooled temperature detection system for a saturated steam system, the subcooled temperature detection system including the following: a plurality of temperature sensors operatively associated with different portions of the saturated steam system; one or more pressure sensors operatively associated with the saturated steam system; and a user interface software coupled to said sensors and one or more saturated steam tables; wherein the user interface software is configured to: calculate a subcooled temperature threshold based on a pressure sensed by the one or more pressure sensors as a function of the one or more saturated steam tables; compare a temperature sensed by each temperature sensor to the calculated subcooled temperature; and send an alarm signal to each temperature sensor having a sensed temperature below the calculated subcooled temperature.

In another aspect of the present invention, the subcooled temperature detection system of claim 1, further comprising a wireless sensor gateway electrically interconnecting said sensors and the user interface software, wherein the one or more pressure sensors are two or more pressure sensors at two or more different portions of the saturated steam system, and wherein the calculated subcooled temperature is a function of a correlation of the two or more sensed pressure of the different portions of the saturated steam system, wherein the alarm signal activates a light the respective temperature sensor, wherein the user interface software is configured to send an electronic message for each alarm signal, wherein each temperature sensor includes a thermocouple, wherein the saturation steam system further comprises a plurality of branches and each branch includes the following one or more steam traps in a wherein the saturation steam system further comprises a plurality of branches and each branch comprises: one or more steam traps in a drip leg; one or more vessels; and an uninsulated piping disposed between the one or more vessels and the drip leg, and wherein one of the plurality of temperature sensors comprising a plurality of branch temperature sensors operatively associated with each branch, and wherein one of each plurality of branch temperature sensors is operatively associated with the uninsulated piping just upstream of the drip leg, wherein each branch temperature sensors measure surface temperature, wherein only one of the one or more pressure sensors is operatively associated with each branch, wherein each plurality of branch temperature sensors of the plurality of temperature sensors are programed to communicate only with the one pressure sensor for the respective branch.

These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an exemplary embodiment of the present invention.

FIGS. 2A-2C show saturated steam tables for the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description is of the best currently contemplated modes of carrying out exemplary embodiments of the invention. The description is not to be taken in a limiting sense but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims.

Referring now to FIGS. 1 through 2C, the present invention may include a method of monitoring a saturated steam system, wherein the method includes a plurality of wireless pressure sensors 1 and a plurality of wireless temperature sensors 2 (with thermocouple) remotely mounted along the saturated steam system 10. A server is in communication with the sensors 1 and 2 as well as electronic lookup tables to use each pressure reading of the plurality of pressure sensors to calculate a theoretically subcooled temperature based on saturated steam tables of the lookup tables.

To be clear, even though FIG. 1 shows a pressure sensor 1 and temperature sensor 2 seemingly in proximity for the sake of illustrating the overall system (wherein the saturated system/steam piping 10 may span the entire floorplan, along dozens of floors, of an entire building), the two types of sensors may or may not actually be within a meter or dozens of meters of each other. As explained more below, a pressure reading (sensed pressure data) may be acquired from a pressure sensor 1 at a first location, wherein this pressure data is used to determine a threshold subcooled temperature that is compared to a temperature reading (sensed temperature data) of a temperature sensor 2 at a second location, wherein the first and second locations may be meters apart, and in different portions of the saturated system 10. Furthermore, the pressure data from the first location may be compared to a plurality of temperature sensors 2 at second, third, . . . n locations, wherein each of these second, third, . . . n locations is dozens of meters away from the first location.

The architecture of the method (and system) of the present invention may include a wireless sensor gateway 3 that manages wireless communications to and from the sensors 1 and 2 and exchanges of data between the sensors 1 and 2 and a connection to a backend, such as a user interface software 4 which is running on a cloud server.

The remote-mounted wireless pressure sensors 1 are configured to send raw steam system pressure values to the user interface software 4 via the wireless sensor gateway 3.

The remote-mounted wireless temperature sensors 2 (with thermocouple) are configured to send raw steam system temperature values to the user interface software 4 via the wireless sensor gateway 3.

The wireless sensor gateway 3 receives the sensor data that is sent by the wireless sensors 1 and 2 and passes this data to the user interface software 4 that is running on a cloud server.

The user interface software 4 takes the pressure sensor readings and correlates the pressures along different portions of the steam system 10 to a calculated theoretical saturated temperature (as determined by use of the saturated steam tables). The temperature at each temperature sensor location is then compared to the calculated theoretical saturated temperature that is based upon the system pressure.

A threshold may be set by, through, and/or via the user interface software 4 so that if a temperature reading at a temperature sensor 2 is outside of the threshold, an alarm will be triggered. The alarm may be an LED light that is flashing on the temperature sensor 2. An e-mail and/or text message may also be sent to the system operator to alert them of this condition.

The systemic steps may include the following: A) read raw pressure data; B) based on this pressure, calculate a theoretical subcooled temperature (using steam lookup tables) based on the sensed pressure; C) comparing sensed temperature and the calculated theoretical subcooled temperatures; D) if temperature is outside of operator-determined threshold, activate an alarm (e.g., a LED blinks on the temperature sensor) and an e-mail or text notification will be sent to the system operator; or E) nothing happens when each sensed saturated temperature is within the calculated subcooled threshold (or range).

The wireless temperature sensors would typically be installed just upstream of the steam traps in a drip leg and critical process applications, on vessels, and other critical parts of the system—wherever subcooling should be monitored. These are to be installed to measure surface temperature so they should be installed on bare, uninsulated piping. These are non-intrusive and install on the exterior of the piping or tubing.

As steam system pressure can vary throughout a system, one wireless pressure sensor would be installed in each branch of the steam system in proximity to a few the temperature sensors. These temperature sensors would be programmed to communicate only with the closest pressure sensor. The gateways 3 may be installed using common industry practices, to maintain communication between the wireless sensors and the cloud server which hosts the user interface software 4

In certain embodiments, the cloud server of network may refer to any interconnecting system capable of transmitting audio, video, signals, data, messages, or any combination of the preceding. The network may include all or a portion of a public switched telephone network (PSTN), a public or private data network, a local area network (LAN), a metropolitan area network (MAN), a wide area network (WAN), a local, regional, or global communication or computer network such as the Internet, a wireline or wireless network, an enterprise intranet, or any other suitable communication link, including combinations thereof.

The server and the computer of the present invention may each include computing systems. This disclosure contemplates any suitable number of computing systems. This disclosure contemplates the computing system taking any suitable physical form. As example and not by way of limitation, the computing system may be a virtual machine (VM), an embedded computing system, a system-on-chip (SOC), a single-board computing system (SBC) (e.g., a computer-on-module (COM) or system-on-module (SOM)), a desktop computing system, a laptop or notebook computing system, a smart phone, an interactive kiosk, a mainframe, a mesh of computing systems, a server, an application server, or a combination of two or more of these. Where appropriate, the computing systems may include one or more computing systems; be unitary or distributed; span multiple locations; span multiple machines; or reside in a cloud, which may include one or more cloud components in one or more networks. Where appropriate, one or more computing systems may perform without substantial spatial or temporal limitation one or more steps of one or more methods described or illustrated herein. As an example and not by way of limitation, one or more computing systems may perform in real time or in batch mode one or more steps of one or more methods described or illustrated herein. One or more computing systems may perform at different times or at different locations one or more steps of one or more methods described or illustrated herein, where appropriate.

In some embodiments, the computing systems may execute any suitable operating system such as IBM's zSeries/Operating System (z/OS), MS-DOS, PC-DOS, MAC-OS, WINDOWS, UNIX, OpenVMS, an operating system based on LINUX, or any other appropriate operating system, including future operating systems. In some embodiments, the computing systems may be a web server running web server applications such as Apache, Microsoft's Internet Information Server™, and the like.

In particular embodiments, the computing systems includes a processor, a memory, a user interface and a communication interface. In particular embodiments, the processor includes hardware for executing instructions, such as those making up a computer program. The memory includes main memory for storing instructions such as computer program(s) for the processor to execute, or data for processor to operate on. The memory may include mass storage for data and instructions such as the computer program. As an example and not by way of limitation, the memory may include an HDD, a floppy disk drive, flash memory, an optical disc, a magneto-optical disc, magnetic tape, a Universal Serial Bus (USB) drive, a solid-state drive (SSD), or a combination of two or more of these. The memory may include removable or non-removable (or fixed) media, where appropriate. The memory may be internal or external to computing system, where appropriate. In particular embodiments, the memory is non-volatile, solid-state memory.

The user interface includes hardware, software, or both providing one or more interfaces for communication between a person and the computer systems. As an example and not by way of limitation, an user interface device may include a keyboard, keypad, microphone, monitor, mouse, printer, scanner, speaker, still camera, stylus, tablet, touchscreen, trackball, video camera, another suitable user interface or a combination of two or more of these. A user interface may include one or more sensors. This disclosure contemplates any suitable user interface and any suitable user interfaces for them.

The communication interface includes hardware, software, or both providing one or more interfaces for communication (e.g., packet-based communication) between the computing systems over the network. As an example and not by way of limitation, the communication interface may include a network interface controller (NIC) or network adapter for communicating with an Ethernet or other wire-based network or a wireless NIC (WNIC) or wireless adapter for communicating with a wireless network, such as a WI-FI network. This disclosure contemplates any suitable network and any suitable communication interface. As an example and not by way of limitation, the computing systems may communicate with an ad hoc network, a personal area network (PAN), a local area network (LAN), a wide area network (WAN), a metropolitan area network (MAN), or one or more portions of the Internet or a combination of two or more of these. One or more portions of one or more of these networks may be wired or wireless. As an example, the computing systems may communicate with a wireless PAN (WPAN) (e.g., a BLUETOOTH WPAN), a WI-FI network, a WI-MAX network, a cellular telephone network (e.g., a Global System for Mobile Communications (GSM) network), or other suitable wireless network or a combination of two or more of these. The computing systems may include any suitable communication interface for any of these networks, where appropriate.

It should be understood, of course, that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims. 

What is claimed is:
 1. A subcooled temperature detection system for a saturated steam system, the subcooled temperature detection system comprising: a plurality of temperature sensors operatively associated with different portions of the saturated steam system; one or more pressure sensors operatively associated the saturated steam system; and a user interface software coupled to said sensors and one or more saturated steam tables; wherein the user interface software is configured to: calculate a subcooled temperature threshold based on a pressure sensed by the one or more pressure sensors as a function of the saturated steam table; compare a temperature sensed by each temperature sensor to the calculated subcooled temperature; and send an alarm signal to each temperature sensor having a sensed temperature below the calculated subcooled temperature.
 2. The subcooled temperature detection system of claim 1, further comprising a wireless sensor gateway electrically interconnecting said sensors and the user interface software.
 3. The subcooled temperature detection system of claim 2, wherein the one or more pressure sensors are two or more pressure sensors at two or more different portions of the saturated steam system, and wherein the calculated subcooled temperature is a function of a correlation of the two or more sensed pressure of the different portions of the saturated steam system.
 4. The subcooled temperature detection system of claim 3, wherein the alarm signal activates a light on the respective temperature sensor.
 5. The subcooled temperature detection system of claim 4, wherein the user interface software is configured send an electronic message for each alarm signal.
 6. The subcooled temperature detection system of claim 5, wherein each temperature sensors includes a thermocouple.
 7. The subcooled temperature detection system of claim 6, wherein the saturation steam system further comprises a plurality of branches and each branch comprises: one or more steam traps in a drip leg; one or more vessels; and an uninsulated piping disposed between the one or more vessels and the drip leg, and wherein one of the plurality of temperature sensors comprising a plurality of branch temperature sensors operatively associated with each branch, and wherein one of each plurality of branch temperature sensors is operatively associated with the uninsulated piping just upstream of the drip leg.
 8. The subcooled temperature detection system of claim 7, wherein each branch temperature sensors measure surface temperature.
 9. The subcooled temperature detection system of claim 8, wherein only one of the one or more pressure sensors is operatively associated with each branch.
 10. The subcooled temperature detection system of claim 9, wherein each plurality of branch temperature sensors of the plurality of temperature sensors are programed to communicate only with the one pressure sensor for the respective branch. 